compression

Video Compression: What is discrete cosine transform?

I've implemented an image/video transformation technique called discrete cosine transform. This technique is used in MPEG video encoding. I based my algorithm on the ideas presented at the following URL: http://vsr.informatik.tu-chemnitz.de/~jan/MPEG/HTML/mpeg_tech.html Now I can transform an 8x8 section of a black and white image, s...

How can I encode xml files to xfdl (base64-gzip)?

Before reading anything else, please take time to read the original thread. A quick simple overview: A .xfdl file is a is a gzipped .xml file which has then been encoded in base64. I wish to de-encode the .xfdl into xml which I can then modify and then re-encode back into a .xfdl file. xfdl > xml.gz > xml > xml.gz > xfdl I have been...

What is the easiest way to add compression to WCF in Silverlight?

I have a silverlight 2 beta 2 application that accesses a WCF web service. Because of this, it currently can only use basicHttp binding. The webservice will return fairly large amounts of XML data. This seems fairly wasteful from a bandwidth usage standpoint as the response, if zipped, would be smaller by a factor of 5 (I actually pas...

ASP.NET gzip compression corrupting CSS

I have an ASP.NET webforms application (3.5 SP1) that I'm working on, and attempting to enable gzip fpr HTML and CSS that comes down the pipe. I'm using this implementation (and tried a few others that hook into Application_BeginRequest), and it seems to be corrupting the external CSS file that the pages use, but intermittently...suddenl...

Best/fastest compression format for (sqlserver) databases?

Has anyone found a good compression format for MS Sqlserver databases? If so, what do you use and are you pleased with how it performs? My company frequently will compress a database snapshot from one of our clients and download it so we have a local copy for testing and dev purposes. We tried zip in the past, but once the database fil...

Does a YUI Compressor GUI App Exist?

I recently discovered Yahoo's YUI Compressor software and started using it on my website. What I'm disappointed about with the software is its lack of a GUI, as well as a lack of a way to combine files. Does anyone know of a project which uses the YUI Compressor as a backend that provides a GUI front-end with the ability to combine fil...

Best javascript compressor

What is the the best Javascript compressor available? I'm looking for a tool that: Easy to use High compression rate Reliable end results (doesn't mess up the code) ...

Why doesn't ZIP Compression compress anything?

A 398MB directory was only compressed to 393MB using 7Z and Normal ZIP compression. Is this normal? If so, why do people continue to use ZIP on Windows? ...

How to compress JPEG images with ASP on Windows CE

The ASP page gets data uses that to draw a graph, I then need to save the image created to JPEG to be displayed on the browser and also used in PDF and other format. What is the best way to compress the image? I am currently porting a JPEG compression library to ASP but I think it will be too slow on this ARM device running Windows CE 6....

Best way to compress HTML, CSS & JS with mod_deflate and mod_gzip disabled

I have a few sites on a shared host that is running Apache 2. I would like to compress the HTML, CSS and Javascript that is delivered to the browser. The host has disabled mod_deflate and mod_gzip, so these options are out. I do have PHP 5 at my disposal, though, so I could use the gzip component of that. I am currently placing the foll...

Zlib-compatible compression streams?

Are System.IO.Compression.GZipStream or System.IO.Compression.Deflate compatible with zlib compression? ...

Are there any compression and encryption libraries in C#?

I want to compress some files (into the ZIP format) and encrypt them if possible using C#. Is there some way to do this? Can encryption be done as a part of the compression itself? ...

Is there a quality, file-size, or other benefit to JPEG sizes being multiples of 8px or 16px?

The JPEG compression encoding process splits a given image into blocks of 8x8 pixels, working with these blocks in future lossy and lossless compressions. [source] It is also mentioned that if the image is a multiple 1MCU block (defined as a Minimum Coded Unit, 'usually 16 pixels in both directions') that lossless alterations to a JPEG ...

How can I determine the length of a .wav file in C#?

In the uncompressed situation I know I need to read the wav header, pull out the number of channels, bits, and sample rate and work it out from there: (channels) * (bits) * (samples/s) * (seconds) = (filesize) Is there a simpler way - a free library, or something in the .net framework perhaps? How would I do this if the .wav file is co...

Does AES (128 or 256) encryption expand the data? If so, by how much?

I would like to add AES encryption to a software product, but am concerned by increasing the size of the data. I am guessing that the data does increase in size, and then I'll have to add a compression algorithm to compensate. ...

What is the best way to pack javascript without getting perfomance flaws?

I am searching for a way to compress javascript for the iphone but don't want to use a lot of cpu time on the small an rather slow device. ...

fastest c++ file compression library available?

I have a need to find the best library to compress in memory data. I am currently using zlib but I am wondering if there is a better compression library; better in terms of performance and memory footprint. It should be able to handle multiple files in the same archive. I am looking for a C/C++ library. Performance is the key factor. ...

compression library for c and php

To save network traffic I'd like to compress my data. The only trick is that I the client is a c application and the server is php. I'm looking for an open source compression library that's available for both c and php. I guess I could write an external c application to decompress my data, but I'm trying to avoid spawning extra processe...

What's a good compression library for Java?

I need to compress portions of our application's network traffic for performance. I presume this means I need to stay away from some of the newer algorithms like bzip2, which I think I have heard is slower. ...

How to search through archived files with Perl

What is your preferred method for reading through the contents of zipped directories with Perl ? ...